While he may have somewhat of a point, and I don't deny that domestic cats will be responsible for the death of some native birds, I would like to see some solid evidence showing that domestic cats are solely responsible for declining numbers of native birds, that eradicating them would reverse this and that their eradication would have other negative effects on other pests (like an increase in rodents).

DOC for example acknowledge that dogs, ferrets and stoats each kill far more kiwi than cats do, yet GM is not calling for the eradication of any of those.

If there is a genuine problem here, which I am not yet fully convinced there is, I think it would be better to address it in a similar way to Australia. Here in Melbourne, I am required by law to register my cats (I have two). Local council by-laws limit me to owning two cats (unless by written exemption). My cats if outside (they never are) must be wearing council issued ID tags at all times and there are heavy penalties for breaching any of these by-laws. My cats are micro chipped and neutered. If they were not, my registration fees would be significantly higher. Many parts of Australia also have by-laws requiring cats be kept inside at night. Breaching any of these laws can mean my cats could be destroyed and/or I be heavily fined.

I think the above approach is a much more sensible way to address this.

Never going to happen and even trying makes him look a bit nutty (unless it's some sort of joke or hoax...?) but I guess I can see where he's coming from: Our cat perfectly fits the "sadists and natural-born killers" label with regards to birds (and then enjoys leaving them as trophies or offerings, sometimes very well dismembered for us to find)

Snakes are kept as pets in many countries and we seem to get by without them...